Quoting JBo (Reply 2):Precisely. However, it is noted that some aircraft were designed and built to withstand a certain number of cycles, beyond which the performance/reliability is not guaranteed.

All current passenger aircraft a "design life goal" a specific number of cycles (one takeoff one landing = one cycle). A the time the "design life goal" is attained the manufacture is required to have an approved program that when incorporated will allow the operator to operate the aircraft beyond the "design life goal".

Some operators my choose to remove aircraft from their fleet before the "design life goal" is met to forgo the expense this added maintenance will require. However, many operator will incorporate these modifications and continue to operated the aircraft until they determine that it is no longer cost effective to continue provide the added maintenance required to continue the aircraft's airworthiness.

Life limit of most aircraft is, as said, basically the point at which it becomes more expensive to keep it airworthy than it would be to replace it.

Quoting flyby519 (Reply 4):There are some older ones getting up over 30k cycles.

I know it's an apples to rear differentials comparison, but we have a 737 in our fleet still going strong with over 70k cycles (and age doesn't matter nearly as much as some people think, we have several aircraft that are multiple years older than it with significantly less cycles)

If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.

Quoting atlengineer (Reply 7):If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.

The DC-9's Design Life Goal is 100,000 cycles, at 70,000 cycles it has lots of life left.

Quoting 474218 (Reply 8):Quoting atlengineer (Reply 7):
If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.

The DC-9's Design Life Goal is 100,000 cycles, at 70,000 cycles it has lots of life left.

Thanks 474218. Do you know what the Design Life Goal is for the MD88's and MD90's?

Quoting JBo (Reply 2):believe the DC-9 will be the only airworthy aircraft after the apocalypse

Sorry, DC-9's will be hauled to the scrap yards in DC-3's and C-130's.....

But more on point, the A380 is likely to first go to the parkling lot not as a result of cycles but as a result of a severe economic downturn making them - and other aircraft - surplus to demand. Now if I could only predict when that would happen.....

Sixty Plus Years of Flying! "I fly because it releases my mind from the tyranny of petty things." - Saint Ex

Quoting Macsog6 (Reply 14):But more on point, the A380 is likely to first go to the parkling lot not as a result of cycles but as a result of a severe economic downturn making them - and other aircraft - surplus to demand. Now if I could only predict when that would happen.....

Actually it would be the opposite, unless the planet encounters a massive reduction in population. Anyway, aircraft are stored, not scrapped. We've just come through a severe economic downturn and many of those stored aircraft are being reactivated now - but note there is not a single A388 or 77W in storage. That's not just because they are new, that's because on average they are the most economic aircraft to keep flying compared to 744s and 343s, especially during a recession. In the A380s case, the only conceivable aircraft which is going to replace it is the A389.

Repairs can go a long way (my understanding is that the old Douglas, Lockheed, and McD products - and even Boeing to some extent - were so rugged that all you needed was to metaphorically "throw a patch on" and go fly. Maybe someone who worked on those beasts (DC-8, DC-10, 707, 727, etc.) can confirm that or not
.

This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped. The two ex-CO 737's in the top-right of the photo even had winglets.

Besides, there are always the lucky few that get turned into restaurants or hotels

Quoting etherealsky (Reply 16):This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped.

The point of Plymspotter is that relative new aircraft will just be stored. Like some 744Fs were stored during the heavy cargo downturn last year but are now reactivated though. On your picture there are only aicraft built before about 1992.
While older aircraft, including MD-80s, 737-300/400/500 (the Continentals were old yet had winglets which probably were salvaged and put on other aircraft) some early A-320s, have been withdrawn to be scrapped, this happens more in a downturn but the current economic boom is not strong enough to save all older 1980s generation aircraft as enough new aircraft come on the market.

I think you are assuming I said they would be scrapped and all I was saying was that economic conditions would likely cause them to be parked before they would ever be ready to be made into billions of beer cans.

Sixty Plus Years of Flying! "I fly because it releases my mind from the tyranny of petty things." - Saint Ex

Quoting MEA-707 (Reply 17):The point of Plymspotter is that relative new aircraft will just be stored. Like some 744Fs were stored during the heavy cargo downturn last year but are now reactivated though. On your picture there are only aicraft built before about 1992. While older aircraft, including MD-80s, 737-300/400/500 (the Continentals were old yet had winglets which probably were salvaged and put on other aircraft) some early A-320s, have been withdrawn to be scrapped, this happens more in a downturn but the current economic boom is not strong enough to save all older 1980s generation aircraft as enough new aircraft come on the market.

Just what I was meaning; new fuel efficient aircraft are not going to be scrapped (yet) - unless they have a serious issue.

I think you are assuming I said they would be scrapped and all I was saying was that economic conditions would likely cause them to be parked before they would ever be ready to be made into billions of beer cans.

Yes sorry, I wasn't aiming the bit about scrapping at you, just a general point.

Corrosion and fatigue are different issues, and corrosion affects both aluminum and steel. Fatigue, however, is what limits aircraft life. Steel, if stressed below a certain point, does not fatigue but has essentially infinite life. Aluminum does not. However, under low stress aluminum can work harden, which makes it stronger. This was discovered when Douglas got worried after WWII about all of the ex-military C-47's being put into civilian service, many with unknown history. They got one that had had a lot of wartime service and subjected it to the same stress tests as they had the original prototype. They were very much surprised to find that the wing failed at about 50% HIGHER load than the original; they ultimately attributed it to work hardening. Again, this is distinct from fatigue, which will still affect it. The main issue for airliners is fatigue from pressurization/depressurization; non-pressurized aircraft are generally not significantly affected by fatigue, with one notable exception: small aircraft used for pipeline inspections have had their wings fail from fatigue due to continual flying at low level in turbulent conditions. This happened to at least one Piper Cherokee, which resulted in an AD requiring removal and inspection of the wings after 5000 hours; this severely impacted the value of Cherokees while it was in force. After several years of inspections and not finding any problems, it was modified to only apply to aircraft subject to severe service, IIRC.

The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler

Quoting etherealsky (Reply 16):This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped. The two ex-CO 737's in the top-right of the photo even had winglets.

KARG is a scrapping facility, not for long term storage. The climate in Arkansas is much too humid, hence the reason most 'boneyards' are in desert locations.

Working very hard to Fly Right....

25 alwaysontherun
: I believe with GA aircraft it is much more simple. No "cycles" as such……… As long as your engine is up to scratch and the airframe is looked aft